Tuyere



Oct. 17, 1933. w. J. HUGHES 1,930,897

' 'TUYERE Original Filed April 13; 1928 2 Sheets-Sheet 1 8 INVENTOl. g: M 216%; fi w:

Oct. 17, 1933.

W. J. HUGHES TUYERE Original Filed April 13, 1928 2 Sheets-Sheet 2 6 a 6 INVENTOR.

- ZIEZZz'am @Z (Hug/26d? Patented Oct. 17, 1933 UNITED STATES TUYERE William John Hughes, Mason City, Iowa, as-

signor to American Engineering Company, a corporation of Pennsylvania Application April 13, 1928, Serial No. 269,85

Renewed April 15, 1932 a 6 Claims.

equipped with mechanical coal feeding means and to which the air for combustion is supplied under pressure.

Steam boilers of large capacity are customarily equipped with apparatus or stokers, whereby the coal used as fuel is introduced into the flre box under the boiler automatically and mechanically by the use of reciprocating plungers, which opi erate to force the coal from a hopper through conduits into the fire box. Between the channels of each pair of adjacent coal conduits there is disposed means for the introduction of air into the coal, whereby the coal may unite with said 5, air and burn. The means commonly employed for admission of air into the coal consists of a series of flat plates or tuyre 'members superposed in stepped rows one above the other between the coal channels. The-tuyeres have suitable openings or passages therethrough, connecting with the air box, of which the row of tuyere members form a wall, whereby the air may flow from said air boxes into the mass of coal. When it is considered that the tuyeres are disposed in the hottest part of the fire box where the temperature runs very high, and when it is also considered that the tuyere members are, for sake of cheapness, made of cast metal, it will be seen that due to the action of the heat, the indi 3o vidual tuyre members of the series can have but a limited life and that it is often necessary to make frequent replacements.

These tuyere members, as heretofore devised, have had their discharge passages or channels extended to the edge of the toe or forward portions thereof, and I have discovered that this results in a direct blast which produces a forging effect at the forward end of the tuyere, with the result that the coal is heated to the melting point of the ash, and, when the ash melts, it flows downwardly on the tuyeres and closes the air discharge passages or channels thereof. This causes the tuyre members to be quickly burned and disintegrated so that replacements are almost constantly necessary.

One object of the invention, therefore, is to provide a tuyere member or block which shall be largely free from the aforementioned tendency to clog and burn and which shall be generally more durable and efficient than the tuyere blocks made in accordance with the prior practice.

Another object of the invention is to provide an improved tuyere member for use at the top of each row of main or primary tuyere members, whereby said main or primary tuyres, are effec- (Cl. 110-44) My invention relates to tuyeres for boilerstively protected from the slag formation, and whereby air is so introduced at the front of the furnace or stoker as to materially promote combustion and thereby produce greater heating efficiency.

Other objects will appear as the nature of the invention is better understood, and the'same consists in the novel form, combination and arrangement of parts hereinafter more fully described, shown in the accompanying drawings 85 and claimed.

In the drawings:

Figure 1 is a fragmentary view, partly in side elevation and partly in vertical section, showing a fire box equipped with a series of tuyeres constructed in accordance with my invention;

Figure 2 is an enlarged bottom plan view of one of the primary tuyres shown in Figure 1;

Figure 3 is a central longitudinal section of the tuyre shown in Figure 2;

Figure 4 is an enlarged perspective view of the secondary tuyere used at the top of the row of primary tuyeres shown in Figure 1;

Figure 5 is a central longitudinal section of the secondary tuyre and the primary tuyere directly therebeneath; and

Figure 6 is a transverse section on line 6-6 of Figure 5.

Referring to Figures 1 to 3 inclusive, the primary tuyere members are shown as consisting each of a body portion in the form of a flat relatively thin plate 5 pointed at its front end and adjacent its straight rear edge provided with an opening or hole 6 for the reception of a projection 7 belonging to a similarly formed tuyere member immediately above it in the stoker. This projection '7 depends from the lower surface of the plate 5 at a point midway between the sides of the latter and forwardly of but in longitudinal alinement with the opening 6 as clearly shown in Figure 2. Depending from the sides of the tuyere plate 5 adjacent the narrower heel or rearward end thereof, are relatively short projections or flanges 8 whose lower edges are beveled as shown clearly in Figures 1 and 3 to conform to the inclination of the walls of the wind box 9 for resting on the latter and supporting the heel end of the tuyere. Formed centrally of the toe portion 10 of the tuyere plate 5 is a depending lug 11 adapted to rest upon the next lower tuyre plate and coast with the lugs or flanges 8 for supportng the tuyeres in a substantially horizontal position, and depending from the lug 11 is an L-shaped lug 12. Provided in the tuyere plate 5 between the lugs 7 and 12 and in lengitudinal alinement with the latter is an opening 13 adapted to receive the lug 12 of the next higher tuyere, the lug 12 of the tuyere shown in Fig. 3 being adapted to enter the opening 13 of the next lower plate. It will be understood that when the lug 12 is entered in the opening 13 of the next lower tuyere of the row, the first member is slid forwardly so as to engage the forwardly projecting lip of the lug 12 under the plate of said next lower member forwardly of the opening 13 of the latter, whereupon the lug 7 will enter the opening 6 of said next lower member. By this means, the members of each stepped row are locked together, and since the tuyere member which lies immediately below that shown in Figure 3 is spaced away from the body of the latter by the lugs 8 and 11, the air from the wind box at the rear of the row flows between the bodies of each pair of adjacent members, escaping from the forward part of the tuyere as will presently become apparent.

The toe portion 10 is formed with a series of vanes or ribs 14, the lower edges of which rest on the top face of the next lower tuyere n the row and also space the bodies of adjacent tuyere members in the row. The spaces between the vanes or ribs 14 form conducting channels or passages for the discharge of air into the coal from the air box. As shown. the ribs 14 are formed with a progressively decreasing pitch from the sides of the toe portion toward the longitudinal center thereof, so that the maximum area of air passage is located at the outer edges of the tuyere members and consequently the greater part of the air discharged therethrough is directed to the greater mass of coal located at the sides of the tuyere.

The air channels or passages are terminated inwardly or rearwardly of the edge of the tuyere toe portion 10, such construction being had where the ribs 14 are employed by terminating said ribs inwardly or rearwardly of the edge of the toe portion 10 as indicated at 15. With this construction, the toe portion of the tuyre plate 5 projects beyond and overlies the outer ends of theair passages or channels, thus protecting the latter from being closed by the melting ash and insuring a maximum life of the tuyere. It has also been found that by terminating the vanes 14 inwardly of the toe edge as. stated above, the air is discharged at a reduced velocity with consequent better air distribution and comparatively high or increased stoker or heating efficiency. The upper surface of the toe portion 10 is also preferably beveled as at 16 to direct the coal and ash beyond the edge of the toe portion 10 and further guard against closing of the air passages or channels between the vanes 14 and between the innermost vanes 14 and the lug 11. Further, the lug 11 is provided with a pointed nose by beveling opposite sides thereof as at 17 to still further enhance the distribution of air as it is discharged at opposite sides of the lug 11.

In view of the provision of the openings 6 and. 13, it has been the usual practice to employ a special tuyere member at the top of each row devoid of such openings and known as a closing plate. These special tuyere members or closing plates are usually of fiat form with bevelled forward or toe ends, and in their use considerable provided an improved form of secondary air supply tuyere members adapted for use at the top of each tuyere to protect the primary tuyere members of each row from the slag formation and to furnish a secondary supply of air at the front of the stoker for producing an improved air distribution and improved combustion.

As shown, my improved secondary air tuyere member embodies a flat hollow base 18 open at the bottom and of a width to have the lower edges of its side walls 19 rest upon the side marginal portions of the tuyere member or plate 5 directly therebelow as shown in Figures 5 and 6. Formed on and communicating with the interior of the base 18, at the forward or toe end of the latter is an upstanding tubular flue 20 of a width corresponding with the width of the base 18 and having a flat rear wall 21 adapted to flatly engage the inner surface of the furnace wall as shown in Figure 1, the sides and front of the flue 20 being rounded to conform with the rounded or tapered form of the toe end of the base 18 as shown. As shown in Figure 5 the secondary tuyere member is adapted to be placed on the uppermost primary tuyre member so that the heel end of the base 18 projects beyond and overhangs said primary member for permitting the passage of air into the base 18 from the air box 9. The air then flows forwardly into and through the flue 20 so as to be discharged through the upper end thereof into the fire box at a point some distance above the uppermost primary member. This location of the flue protects the primary tuyere member from the slag formation as stated above, and provides for a secondary introduction of air for promoting combustion and insuring greater heating or stoker efficiency. Provided in the upper Outlet end of the flue 20 are a series of spaced transverse ribs or vanes 22 which are inclined upwardly and forwardly so as to direct the discharge of air into the fire box at a corresponding angle. This insures a secondary admission of air distributed so as to result in substantially complete combustion. Formed on the front or toe end of the secondary tuyre member at the base of the fiue 20 is a forwardly projecting horizontal ear 23 adapted to rest upon the upper surface of the top primary tuyere plate 5 of the row and to cover the opening 13 of the latter, the secondary tuyere member being secured to this top primary member 5 and maintained in place by bolting as at 24 through the ear 23 and the opening 13 of said top primary member, as shown in Figure 5.

I am of course aware of the fact that the means for connecting the primary tuyeres of each row or series is old per se as shown in the U. S. patent to M. Alpem No. 1,123,063, dated December 29th, 1914. I am also aware of the fact that it is broadly old to provide the spaced fins or teeth 14 at the toe end of the tuyere for defining the air discharge channels or passages, as shown in the U. S. patent to L. E. Thompson, 1,293,985, dated February 11, 1919. It is accordingly to be understood that I have illustrated the form of tuyere shown in Figures 1 to 3 inclusive, merely by way of example, and to disclose a constructhe improved results enumerated above, when modified as shown to embody the novel feaarturesv of the present invention.

From the foregoing description it is believed that the construction, manner of use, and advantages of the present invention will be readily apparent to those skilled in the art.

Minor changes may be made without departing from the spirit and scope of the invention as claimed.

What I claim as new is:-

1. A tuyere member having a portion adapted in assembly to form a substantially horizontal fuel-supporting surface, said portion having depending ribs deflning air channels, and said ribs terminating inwardly of the edge of said fuelsupporting portion.

2. A tuyere block having a substantially horizontal fuel-supporting portion, and means defining air channels on the under side thereof, said channels terminating at a point inwardly of the edge of said fuel-supporting portion.

3. A tuyere block comprising a body portion ineluding a plurality of air channels, and a fuel-supporting portion overlying and projecting in a substantially horizontal direction beyond the ends of said channels.

4. A tuyere member comprising a substantially flat plate affording in assembly a substantially horizontal fuel-supporting surface, said plate having on its nether side a plurality of air channels terminating inwardly of the edge of said 5. A tuyere block, comprising a substantially flat fuel supporting portion, having on its nether side depending means defining air channels, said means terminating inwardly of the edge of said fuel supporting portion, and the ends of said means and the projecting edge of said fuel supporting portion forming in eifect a channel which communicates with said first mentioned air chanins 

